I always pause and hope they will figure it out...
Unfortunately, this never happens...
Example 1 - ordering food in a restaurant;
Me: "A garden-burger with no mayonnaise, please."
Waiter: "Oh, it doesn't come with mayonnaise." (waits for a response from me)
Me: "Okay ....(long pause) ....then keep it like that."
Example 2 - my day job, as an order taker for a courier service;
Phone: "How much time do we need?"
Me: "More than an hour is guaranteed."
Phone: "So, how about if I give you two hours?"
Me: "......." (long pause)
Phone: "Would two hours be guaranteed?"
Me: "...... .... that's more than an hour, so yes."